Device for assembling framed screens



BLING FRAMED SCREENS 7 Sheets-Sheet 1 Filed Dec. 1, 1952 INVENTOR Owew ConracL.

ATTORNEY July 10, 1956 o. CONRAD DEVICE FOR ASSE MBLING FRAMED SCREENS 7 Sheets-Sheet 2 Filed Dec. 1. 1952 INVENTOR Owero Conrad.

ATTORNEY O. CONRAD DEVICE FOR ASSEMBLING FRAMED SCREENS 7 Sheets-Sheet 3 Filed Dec. 1. 1952 INVENTOR Owen/ Conrad.

ATTORNEY July 10, 1956 o. CONRAD DEVICE FOR ASSEMBLING FRAMED SCREENS 7 Sheets-Sheet 4 Filed Dec. 1, 1952 Owen C'ofirad.

ATTORNEY July 10, 1956 o. CONRAD 2,753,897

DEVICE FOR ASSEMBLING FRAMED SCREENS Filed Dec. 1, 1952 7 Sheets-Sheet 5 Owen/ Conrad.

A ORNEY July 10, 1956 o. CONRAD DEVICE FOR ASSEMBLINGYFRAMED SCREENS 7 Sheets-Sheet 6 Filed Dec. 1, 1952 INVENTOR i I u ATTORNEY Owem Conrad.

July 10, 1956 o. CONRAD DEVICE FOR A SSEMBLING FRAMED SCREENS 7 Sheets-Sheet 7 Filed Dec. 1, 1952 I INVENTOR/ 9 Owem Conrad.

ATTORNEY United States Patent DEVICE FOR ASSEMBLING FRAMED SCREENS Owen Conrad, Miami, Fla., assignor to American Screen Products Company, a corporation of Florida Application December 1, 1952, Serial No. 323,401

8 Claims. (Cl. 140-109) This invention relates to framed screens and is more particularly concerned with assembly machines for use in securing the screening to the frame with splines set into grooves.

More particularly, the invention is designed to facilitate the assembly of preformed members which, when properly united, form a framed insert screen. These members consist of a grooved frame, a sheet of screening, and splines. The screening is fastened to the frame by bending its edges down into the grooves surrounding the inner perimeter of the frame and then forcing the splines into the grooves. In accordance with conventional practice, such screens are assembled by laying the frame, grooves up, flat on the table, placing a precut sheet of screening on top of the frame, turning the edges of the screening into the groove by rolling a hand tool along the groove and then driving home each spline in turn with a hammer. The quality of the finished product depends largely upon the skill and care exercised by the workman. Moreover, this hand method of assembly, makes it difficult to produce a high quality finished prodnot due to the fact that the splines are hammered in one at a time so that uniform tensioning of the screen over its entire area in all directions is not usually obtained, even by very skilled persons.

One of the objects of the present invention is the provision of amachine for use in assembling framed screens of the type mentioned which results in superior and uniform quality of finished product and which, moreover, can be operated by relatively unskilled persons.

Another object of the invention is the provision of such a machine which reduces the time necessary to make the assembly, increases the productive output of each worker, decreases unit cost, and improves working conditions by eliminating or reducing noise and physical exertion on the part of the operators.

Further objects and advantages of this invention will appear from the following description considered together with the accompanying drawing.

In the drawing:

Fig. l is a side elevational view of an embodiment of the invention.

Fig. 2 is an end elevational view of the same embodiment.

. Fig. 3 is a plan view of the embodiment, partly broken away.

Fig. 4 is a side elevational view of one of the tables.'

Fig; 4(a) is an enlarged fragmentary portion, partly in section, of the table shown in Fig. 4.

Fig. 5 is a section along the line 5-5 of Fig. 3, showing the position of the screen frame members before assembly.

Fig. 6 is a view of the screen frame members as shown in Fig. 5, apart from the assembly machine, and in spaced relation to each other.

Fig. 7 is a view similar to Fig. 5 showing the screen frame members in assembled position under the influence of the pressure platen.

ice

Fig. 8 is a fragmentary .view showing the assembled screen and assembly machine elements as the assembled screen is discharged from the machine.

Fig. 9 is a perspective view of a longitudinal portion of one of the assembly tables.

Referring with more particularity to the drawing in which like numerals designate like parts, the embodiment illustrated comprises a rectangular, box-like, frame structure, designated generally by the numeral 11. The device as a whole has three principal sections, namely, the center section A, and two end sections B and C, respectively.

The end sections are provided with tables 12 and 13, respectively, which are slidably mounted on parallel longitudinal tracks 14 secured on top of the frame 11. Rabbeted cleats 15 are secured to the bottom of the table 12, similar cleats to the bottom of the table 13, and they slidably engage the tracks 14, substantially as shown, thereby providing a space between the bottom of the tables and top of the frame 11.

The tables are adapted to reciprocate horizontally on the tracks between their respective end sections and the center section A.

The center section is provided with a pressure platen 16 which is vertically reciprocated on four posts 17. These posts are secured to and project upwardly from suitable brackets 18 attached to the side of the frame structure 11. Vertical reciprocation of the pressure platen 16 is effected by a camming arrangement comprising a transverse cam shaft 19 rotatably mounted in bearings 20, 21 and 22 on the frame structure 11. A pair of circular cams 23 and 24 are eccentrically secured to the ends of the shaft and are rotatably engaged with eccentric straps 25 and 26, respectively. Each strap is carried at one end of an eccentric rod 27 and 28, the other end of the rods being pivotally journaled to pins 29 and 30 projecting laterally from the platen 16. Consequently, rota tion of the shaft 19 results in the vertical reciprocation of the platen. The rods 27 and 28 are each made adjustable in length by means of adjustable joints 31 and 32, respectively.

Rotation of the cam shaft 19 is effected by an electric motor 33 or other suitable source of power, having a take-off shaft 34 geared to a counter-shaft 35 by means of belts 36 and pulleys 37 and 38. The counter-shaft -is mounted in frame bearings 39 and 40 and carries for constant rotation therewith an intermediate gear 41 which is constantly in mesh with a driven gear 42. The latter gear is rotatably mounted on the cam shaft 19. The gear 42 and shaft 19 are selectively engageable for corotation by means of a clutch 43 mounted on the shaft 19 controlled by an arm 44. The arm may be operated by any suitable means, such as a solenoid 45. The shaft 19 may also be provided with a dash pot in the form of a drag brake 46 to stop rotation of the cam shaft under its own momentum when the clutch is released and comprises a brake drum 47 on the shaft and a brake band 48 in engagement with the drum.

Each table 12 and 13 carries a unit for supporting the screen frame elements and the sheet of screening prior to and during assembly under the force of the pressure platen. Each of these units comprises a base member 49 secured to the table by bolts 50 or any other suitable means. Secure on top of the base member 49 are end strips 51 and side strips 52 with bolts 53 and 54, respectively. A vertical wall 55 is mounted on the strips 51 and 52 and extends around the sides and ends thereof in the form of a rectangle. Adjacent the outer sides of the wall 55 there is secured rectangular shelf 56, the top of which is below the top of the wall 55. The shelf 56 supports an outer floating frame carrier 57 consisting of members 58 at the ends and 59 at the sides, said members being connected together by corner pieces or flat angles 60.

Coil springs 61 floatingly support the carrier 57 on the shelf 56. The lower ends of the springs 61 are held in cylindrical recesses 62 at the top of the said shelf, the upper ends of said springs abutting the bottom of the floating carrier 57. Bolts 63 project upwardly through vertical countersunk apertures 64 in the strips 51 and 52 and apertures 65 of the shelf. The upper ends of the bolts have each a reduced threaded section 66 which is screwed into the bottom of the carrier 57. Accordingly, as the carrier moves downwardly, the bolts'slide through the apertures 64 and 65 until the head 67 on the bottom of the bolts contacts the top of the table, an aperture 68 being provided through the base member 49 to accommodate each bolt head during this movement.

Outer abutment plates 69 are secured to the shelf 56 and project upwardly in slidable engagement with the floating carrier 57 to assist in holding it in proper position.

The upper inside corners of the floating carrier 57 are rabbeted to provide a continuous rectangular recess 70 of L-shaped section for supporting the frame of the screen to be assembled. The horizontal ledge 71 of the recess is, in its normal position, above the top edge of the wall 55.

On the inner side of the wall 55, another floating carrier 72, comprising end members 72A and side members 72B is provided on coil springs 73. The upper ends of the springs 73 are carried in recesses 74 at the bottom of the carrier 72 and the lower end of the springs rest on top of the stationary frame 51. Bolts 75 pass upwardly through countersunk apertures 76 in the strips 51 and 52, through the coil springs 73 and are secured to the movable inner floating carrier 72 by means of a reduced threaded portion 77 at the upper end. Apertures 78 are provided through the base member 49 to accommodate the heads 79 of the bolts which function in a manner similar to the bolts 63, hereinabove described.

The carrier 72 is also rabbeted at the inside corner to provide a recess 80 which supports a sheet 81 of thin plywood or other suitable material, such as Masonite, and which, in turn, supports the screening 82 to be assembled with the screen frame.

The top edge 83 of the carrier 72 projects upwardly above the top edge of the wall 55 an amount substantially equal to the thickness of the spline 84 that are to form part of the assembled screen and the thickness of the wall is substantially equal to the width of the splines.

Inner abutment plates 85 are attached to the inside of the strips 51 and 52 and they project upwardly to slidably engage the inner carrier 72 and help hold it in proper POSl'ElOIl.

The screen parts to be assembled consist of the usual rectangular frame 86 formed with channels 87 on one face at the inner perimeter for receiving the border edges of the sheet of screening 82 and splines 84 which are tightly wedged into the channels and hold the screening in place. In making the assembly with the device hereinabove described, the splines 84 are first placed on top of the wall 55 between the vertically movable floating carriers 57 and 72. The screening 82, cut to the proper size, is then placed on the sheet 81 and over the splines the edges thereof extending to the outer floating carrier 57. The screen frame 86, is then placed above the sheet of screening and supported in the rabbeted recess 70 of the outer floating carrier 57.

The entire table is then moved along the tracks 14 to the center section A of the device until it is directly beneath the platen 16 at which time the clutch 43 is actuated to rotatably connect the shaft 19 with the driven gear 42, thereby causing the platen to move downwardly. Under the pressure of the platen, the border edges of the sheet of screening 82 and the splines 84 are forced into the channels 87, as shown in Fig. 7, the floating carriers 57 and 72 yielding under the pressure. By this action, the screening 82 is pulled taut in both horizontal direction 4 simultaneously, and is prevented from being distorted in a vertical direction due to the fact that the inner-lip 88 of the channel is directly above and bears against the inner floating carrier 72.

The platen then moves upward and the table is returned to its original loading position, whereupon the assembled screen is removed and the table reloaded for the next assembly. Slots 89 are provided in the outer floating carrier 57 to facilitate the manual placing of the frame element 86 and the removal of the assembled frame.

The operation of the device is preferably so arranged that as one of the tables 12 or 13 is being loaded for assembly, the other table, already loaded, is moving under the platen. In other words, the cycle of operation of the two tables should be synchronized to conserve as much time as possible.

Although the tables may be moved on the tracks to and from the center section manually, they may also be moved mechanically, if desired. One means for doing this is by the use of hydraulic jacks 90 and 91, one for each table 12 and 13, respectively. These jacks are secured by footplates 92 and 93 to the top of the frame structure 11 below the tables 12 and 13, and the ends of the piston rods 94 and 95 are secured to brackets 96 and 97 on the bottom of the opposite table. Pipe lines 98 and 99 from a source of fluid under pressure (not shown) are connected to the ends of the cylinders of the jacks through suitable 4-way control valves 100 and 100A.

The actuation of said jacks may, furthermore, be automatically synchronized, if desired, with each other and with the vertical movement of the platen by a suitable electrical circuit, containing starting switches 101 and 101A, limit switches 102 and 102A, microswitches 103 and 103A operated by fingers 104 and 104A carried by the movable tables, and microswitches 105 and 105A operated by members 106 and 106A attached to the tables in opposite relation. A microswitch 107 on top of one of the platen posts 17 would be contacted by the platen at the limit of its upward travel. The hydraulic valves would be operated by solenoids 108 and 108A. These electrical elements may be connected in an electrical circuit, if automatic synchronized action is desired, to function as follows: To start the cycle of operation with the table 12, for example, the starting switch 10 which controls the hydraulic circuit, would be first closed to energize the solenoid 108 on the four-way valve 100, thereby releasing the flow of oil into the return end 109 of the hydraulic jack cylinder 90 and causing its piston rod 94, connected to the table 12, to move to the center section A under the platen. As the table begins moving toward the center of the machine, a cam 110 attached thereto contacts its corresponding limit switch 102 and thereby neutralizes the entire electrical and hydraulic circuit of the opposite table 13. When the table 12 has thus been set in motion and it reaches its proper position at the center section A, the finger 106 contacts its corresponding microswitch 105, deenergizing solenoid 108 and thus neutralizing the hydraulic valve 100. At the same time, the clutch solenoid 45 is energized to bring into action the clutch 43 and cause the shaft 19 to rotate for one revolution, whereby the action of the cams brings the platen down and then returns it to the top, its original position, where contact is made with the microswitch 107. Actuation of the latter neutralizes the solenoid 108 on the four-way valve 100 and energizes the solenoid 108A on the other four-way valve 100A, thereby releasing hydraulic pressure on the extension end 111 of the hydraulic cylinder 90 to return the table 12 to its original loading position. As the table moves into this position, the finger 104 contacts the microswitch 103 which de-energizes the solenoid 108 together with its operating current and energizes the solenoid 108A. Also the limit switch 102 is released from the cam 110 permitting the circuit for the table 13 to become operational and pass through a similar cycle, this cycle being started by the energizing of the solenoid 108A to operate the valve 100A and start the table 13 moving to the center section.

When a table returns to its original loading position after passing through this cycle of operations, the operator removes the completed screen. In the meantime, the operator at the other table has placed the screen parts thereon in preparation of the next cycle of operations.

I claim:

1. A device for assembling elements of framed screens, said elements consisting of a frame having grooves on a face thereof, a sheet of screening, and splines adapted to be disposed in the grooves of the frame together with border edges of the screening; said device comprising a table; a rigid structure for supporting said table; said table being slidable over said structure between a loading station and an assembly station; a member carried by the table for rigidly supporting said splines; a first floating carrier on said table extending above said member, for yieldably supporting said sheet of screening; a second floating carrier on said table extending above said first floating carrier, for yieldably supporting said frame; and a vertically reciprocatable platen above said table at said assembly station for applying pressure downwardly on said frame and carriers.

2. A device for assembling elements of framed screens, said elements consisting of a frame having grooves on a face thereof, a sheet of screening, and splines adapted to be disposed in the grooves of the frame together with border edges of the screening; said device comprising a table; a rigid structure for supporting said table; said table being slidable over said structure between a loading station and an assembly station; means for moving said table between said stations; a member carried by the table for rigidly supporting said splines; a first floating carrier on said table extending above said member, for yieldably supporting said sheet of screening; a second floating carrier on said table extending above said first floating carrier, for yieldably supporting said frame; and a vertically reciprocatable platen above said table at said assembly station for applying pressure downwardly on said frame and carriers.

3. A device for assembling elements of framed screens, said elements consisting of a frame having grooves on a face thereof, a sheet of screening, and splines adapted to be disposed in the grooves of the frame together with border edges of the screening, said device comprising a horizontal trackway extending from a loading station to an assembly station, a table slidably mounted on said trackway for movement between said stations, a member carried by the table for rigidly supporting said splines; a first floating carrier on said table extending above said member, for yieldably supporting said sheet of screening; a second floating carrier on said table extending above said first floating carrier, for yieldably supporting said frame; and a vertically reciprocatable platen above said table at said assembly station for applying pressure downwardly on said frame and carriers.

4. A device for assembling the elements of framed screens, said elements consisting of a frame having grooves on a face thereof, a sheet of screening, and splines adapted to be disposed in the grooves of the frame together with border edges of the screening, said device comprising a table, a member carried by the table for rigidly supporting said splines; a first floating carrier on said table extending above said member, for yieldably supporting said sheet of screening, and a second floating carrier on said table extending above said first floating carrier, for yieldably supporting said frame, whereby said elements, when positioned on said member and carriers can be assembled by pressing downwardly on said frames.

5. A device as defined by claim 4 in which the carriers are supported on coil springs disposed between each of them and the table.

6. A device as defined by claim 4 in which the floating carriers are disposed adjacent the member and on either side thereof to form a trench for the splines.

7. A device as defined by claim 4 having abutment means between the table and the floating carriers to limit the relative movement thereof.

8. A device as defined by claim 4 in which the second floating carrier is provided with lateral abutments for the outer edges of the frame.

References Cited in the file of this patent UNITED STATES PATENTS 1,714,468 Espenschied May 21, 1929 1,863,073 Smythe June 14, 1932 2,339,032 Schlenzig Jan. 11, 1944 2,410,694 Tyler Nov. 5, 1946 2,603,856 Nelson July 22, 1952 

